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from __future__ import absolute_import, division, print_function
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import copy
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from ._compat import iteritems
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from ._make import NOTHING, fields, _obj_setattr
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from .exceptions import AttrsAttributeNotFoundError
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def asdict(inst, recurse=True, filter=None, dict_factory=dict,
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retain_collection_types=False):
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"""
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Return the ``attrs`` attribute values of *inst* as a dict.
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Optionally recurse into other ``attrs``-decorated classes.
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:param inst: Instance of an ``attrs``-decorated class.
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:param bool recurse: Recurse into classes that are also
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``attrs``-decorated.
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:param callable filter: A callable whose return code deteremines whether an
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attribute or element is included (``True``) or dropped (``False``). Is
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called with the :class:`attr.Attribute` as the first argument and the
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value as the second argument.
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:param callable dict_factory: A callable to produce dictionaries from. For
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example, to produce ordered dictionaries instead of normal Python
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dictionaries, pass in ``collections.OrderedDict``.
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:param bool retain_collection_types: Do not convert to ``list`` when
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encountering an attribute whose type is ``tuple`` or ``set``. Only
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meaningful if ``recurse`` is ``True``.
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:rtype: return type of *dict_factory*
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:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
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class.
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.. versionadded:: 16.0.0 *dict_factory*
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.. versionadded:: 16.1.0 *retain_collection_types*
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"""
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attrs = fields(inst.__class__)
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rv = dict_factory()
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for a in attrs:
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v = getattr(inst, a.name)
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if filter is not None and not filter(a, v):
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continue
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if recurse is True:
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if has(v.__class__):
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rv[a.name] = asdict(v, recurse=True, filter=filter,
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dict_factory=dict_factory)
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elif isinstance(v, (tuple, list, set)):
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cf = v.__class__ if retain_collection_types is True else list
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rv[a.name] = cf([
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asdict(i, recurse=True, filter=filter,
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dict_factory=dict_factory)
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if has(i.__class__) else i
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for i in v
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])
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elif isinstance(v, dict):
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df = dict_factory
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rv[a.name] = df((
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asdict(kk, dict_factory=df) if has(kk.__class__) else kk,
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asdict(vv, dict_factory=df) if has(vv.__class__) else vv)
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for kk, vv in iteritems(v))
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else:
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rv[a.name] = v
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else:
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rv[a.name] = v
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return rv
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def astuple(inst, recurse=True, filter=None, tuple_factory=tuple,
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retain_collection_types=False):
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"""
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Return the ``attrs`` attribute values of *inst* as a tuple.
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Optionally recurse into other ``attrs``-decorated classes.
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:param inst: Instance of an ``attrs``-decorated class.
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:param bool recurse: Recurse into classes that are also
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``attrs``-decorated.
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:param callable filter: A callable whose return code determines whether an
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attribute or element is included (``True``) or dropped (``False``). Is
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called with the :class:`attr.Attribute` as the first argument and the
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value as the second argument.
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:param callable tuple_factory: A callable to produce tuples from. For
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example, to produce lists instead of tuples.
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:param bool retain_collection_types: Do not convert to ``list``
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or ``dict`` when encountering an attribute which type is
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``tuple``, ``dict`` or ``set``. Only meaningful if ``recurse`` is
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``True``.
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:rtype: return type of *tuple_factory*
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:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
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class.
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.. versionadded:: 16.2.0
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"""
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attrs = fields(inst.__class__)
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rv = []
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retain = retain_collection_types # Very long. :/
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for a in attrs:
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v = getattr(inst, a.name)
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if filter is not None and not filter(a, v):
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continue
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if recurse is True:
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if has(v.__class__):
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rv.append(astuple(v, recurse=True, filter=filter,
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tuple_factory=tuple_factory,
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retain_collection_types=retain))
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elif isinstance(v, (tuple, list, set)):
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cf = v.__class__ if retain is True else list
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rv.append(cf([
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astuple(j, recurse=True, filter=filter,
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tuple_factory=tuple_factory,
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retain_collection_types=retain)
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if has(j.__class__) else j
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for j in v
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]))
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elif isinstance(v, dict):
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df = v.__class__ if retain is True else dict
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rv.append(df(
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(
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astuple(
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kk,
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tuple_factory=tuple_factory,
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retain_collection_types=retain
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) if has(kk.__class__) else kk,
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astuple(
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vv,
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tuple_factory=tuple_factory,
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retain_collection_types=retain
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) if has(vv.__class__) else vv
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)
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for kk, vv in iteritems(v)))
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else:
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rv.append(v)
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else:
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rv.append(v)
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return rv if tuple_factory is list else tuple_factory(rv)
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def has(cls):
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"""
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Check whether *cls* is a class with ``attrs`` attributes.
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:param type cls: Class to introspect.
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:raise TypeError: If *cls* is not a class.
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:rtype: :class:`bool`
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"""
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return getattr(cls, "__attrs_attrs__", None) is not None
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def assoc(inst, **changes):
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"""
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Copy *inst* and apply *changes*.
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:param inst: Instance of a class with ``attrs`` attributes.
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:param changes: Keyword changes in the new copy.
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:return: A copy of inst with *changes* incorporated.
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:raise attr.exceptions.AttrsAttributeNotFoundError: If *attr_name* couldn't
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be found on *cls*.
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:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
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class.
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.. deprecated:: 17.1.0
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Use :func:`evolve` instead.
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"""
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import warnings
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warnings.warn("assoc is deprecated and will be removed after 2018/01.",
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DeprecationWarning)
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new = copy.copy(inst)
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attrs = fields(inst.__class__)
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for k, v in iteritems(changes):
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a = getattr(attrs, k, NOTHING)
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if a is NOTHING:
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raise AttrsAttributeNotFoundError(
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"{k} is not an attrs attribute on {cl}."
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.format(k=k, cl=new.__class__)
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)
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_obj_setattr(new, k, v)
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return new
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def evolve(inst, **changes):
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"""
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Create a new instance, based on *inst* with *changes* applied.
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:param inst: Instance of a class with ``attrs`` attributes.
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:param changes: Keyword changes in the new copy.
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:return: A copy of inst with *changes* incorporated.
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:raise TypeError: If *attr_name* couldn't be found in the class
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``__init__``.
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:raise attr.exceptions.NotAnAttrsClassError: If *cls* is not an ``attrs``
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class.
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.. versionadded:: 17.1.0
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"""
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cls = inst.__class__
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attrs = fields(cls)
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for a in attrs:
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if not a.init:
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continue
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attr_name = a.name # To deal with private attributes.
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init_name = attr_name if attr_name[0] != "_" else attr_name[1:]
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if init_name not in changes:
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changes[init_name] = getattr(inst, attr_name)
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return cls(**changes)
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